Waterloo region sees earlier rise in flu cases and hospitalizations

Waterloo region reports an earlier-than-usual surge in influenza linked to a new H3N2 variation, with rising cases, hospitalizations and high test positivity.

Waterloo Region is experiencing a notably early increase in influenza cases and hospitalizations this season, and local health officials say a new variation of the H3N2 strain may be contributing to the surge. David Aoki, director of infectious disease and chief nursing officer for the Region of Waterloo, described this as “a much earlier kind of rise in cases” compared with recent years and said the circulating H3N2 is an entirely different strain than seen previously. What the data show - To date, 503 flu cases have been reported this season in the region, with 156 cases—nearly a third of the total—reported in the week ending Dec. 20. Public Health Ontario reported a high lab-confirmed influenza test positivity of 27.8% for the week ending Dec. 13. Uncertainties and risk groups - Aoki cautioned it is still early in the season and health officials have not yet seen the peak; it is unclear whether the current rise will plateau or continue to increase. He also noted it is difficult at this stage to say definitively whether the new H3N2 variation is the direct cause of higher hospitalization rates. - The strain can affect people of any age, but local case counts so far are concentrated among those above 60 and children under about 12. Officials highlighted particular concern for the very young, older adults and people with underlying health conditions or weakened immune systems. Vaccine and protection - Current vaccines are not a perfect match to this H3N2 variation, but Aoki emphasized that vaccination remains the best form of protection. Even in years with a vaccine–strain mismatch, vaccines can reduce severe outcomes such as pneumonia, hospitalizations and deaths. Suggested steps to reduce spread - Consider staying home when feeling unwell, wash hands frequently, cover your mouth when coughing and wear a mask in enclosed spaces; consider vaccination to reduce the risk of severe illness.